Rotating plate double-panel PET system based on polygon view symmetry and imaging method thereof

Abstract

The invention discloses a rotating plate double-panel PET system based on polygon view symmetry. The system can obtain multi-angle projection data and solve the problem that a panel PET system can not obtain complete angle projection data. The invention further discloses an imaging method based on the system. The method comprises the following steps that a data collecting module is used for obtaining the complete angle projection data; a view, a coding crystal and a response line are divided, and required voxel and corresponding line codes are determined and calculated; a polygon view system response matrix is calculated, and the system response matrix and the projection data are utilized for carrying out iteration reconstruction; the polyhedral voxel is converted into the cube voxel, and image display is carried out. According to the method, the symmetry of the polygon view structure is utilized, limitation on the symmetry of the rotating system from the square view structure is broken, the calculation amount of the system matrix is reduced, and the reconstruction efficiency of the PET system is improved; by adjusting the size of sectors in the view, the method can be widely applied to the rotating panel PET system.

Description

technical field [0001] The invention relates to the field of nuclear medicine imaging, in particular to a rotating double-plate PET system based on the symmetry of a polygonal field of view and an imaging method thereof, which can be applied to in vivo imaging of small animals. Background technique [0002] PET (Positron Emission Tomography, PET) stands for Positron Emission Tomography, which is an advanced imaging technology in the field of nuclear medicine. PET technology uses anatomical morphology to perform functional, metabolic and receptor imaging techniques, especially in the early detection of tumors, which can not be ignored. Most of the traditional PET detectors use the static ring mode. Although the sampling of the complete angle can be obtained, the complexity of the system is high and the cost is high. At the same time, the ring structure is highly closed, causing unnecessary mental pressure to the sampled object. At the same time, it does not It is convenient ...

AI Technical Summary

Problems solved by technology

Most of the traditional PET detectors use the static ring mode. Although the sampling of the complete angle can be obtained, the complexity of the system is high and the cost is high. At the same time, the ring structure is highly closed, causing unnecessary mental pressure to the sampled object. At the same time, it does not It is convenient for doctors or experimenters to provide technical guidance on sampling objects; in order to reduce costs and increase the flexibility of the detector, some researchers have proposed a flat-panel PET detector. Since it is impossible to obtain projection data from a complete angle, and at the same time, there is a serious depth response. It has an impact on the imaging effect. For example, Chien-Min Kao et al. proposed a static double-head flat-panel PET detector in the article "Evaluation of 3D Image Reconstruction Methods for a Dual-Head Small-Animal PET Scanner", which reduces the The complexity of the system structure, but the projection data of the complete angle cannot be obtained;

[0003] The system response matrix (System Response Matrix, SRM) is a bridge connecting the detector and the tracer. As a mathematical description of the imaging process of the detector system, its calculation mainly includes experimental methods, analytical methods and Monte Carlo simulation methods. The method has high requirements on the experimental conditions, and the operation is complicated. The Monte Carlo simulation method has a relatively low ability to suppress noise, is easily affected by noise, and the simulation time is relatively long. Although the analytical method cannot accurately describe the tracer decay Physical process, but the calculation time is less, and it is easy to implement; the calculation of the system response matrix is ​​a key factor in PET reconstruction, its scale is often very large, it is difficult to guarantee real-time processing, and its calculation, storage and recall efficiency has become a research topic. In order to reduce the complexity of the system response matrix, some researchers proposed to use the symmetry of the detector system to reduce the number of calculation response lines or reduce the number of calculation voxels

Tsinghua University disclosed a static double-plate PET symmetry method based on response lines in its patent application "An image reconstruction method for double-plate PET detectors" (patent application number 201310055434.7, publication number CN103099637A), which simplifies to a certain extent The calculation of the system response matrix is ​​improved, and the compression ratio of the system response matrix is ​​improved, but the voxel needs to be expanded during the simulation, which increases the complexity of the simulation process, thus limiting the calculation efficiency of the system response matrix to a certain extent, and This method only works for static flat PET and is no longer applicable for rotating systems; June et al. proposed in the article "Efficient methodologies for system matrix modeling in iterative image reconstruction for rotating high-resolution PET" to use the axial symmetry and inter-plane symmetry of the system to improve the calculation efficiency of the system matrix. In view of its cube pixel structure, the limitation The symmetry of the rotating system is played

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